Four-Winged Dinosaurs Found in China, Experts Say

[Scorpius]

Paleontologists in China have discovered the fossil remains of a four-winged dinosaur with fully developed, modern feathers on both the forelimbs and hind limbs. The new species, Microraptor gui, provides yet more evidence that birds evolved from dinosaurs, and could go a long way to answering a question scientists have puzzled over for close to 100 years: How did a group of ground-dwelling flightless dinosaurs evolve to a feathered animal capable of flying? Xu Xing, a paleontologist at the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, China, and colleagues suggest in the January 23 issue of the journal Nature that the species is an early ancestor of birds that probably used its feathered limbs, along with a long, feather-fringed tail, to glide from tree to tree. Paleontologists in China have discovered the fossil remains of a four-winged dinosaur with fully developed, modern feathers on both the forelimbs and hind limbs.

The new species, Microraptor gui, provides yet more evidence that birds evolved from dinosaurs, and could go a long way to answering a question scientists have puzzled over for close to 100 years: How did a group of ground-dwelling flightless dinosaurs evolve to a feathered animal capable of flying?

View: Full Article | Source: National Geographic

Edited February 7, 2004 by SaRuMaN

[Benjo Koolzooie]

Nice article Blue-Scorpion .

Thanks for sharing that with us.

[cee1]

Paleontologist Questions Claims of Four-Winged DinoBird 05/19/2003

Kevin Padian, curator of the UC Berkeley museum of paleontology, is not sure what to think about the fossil of an alleged theropod with feathers on all four limbs, named Microraptor gui, announced in Nature last January.

Writing in the May issue of Bioscience, he thinks it is potentially as important as Archaeopteryx “if the claims pan out” (which he feels are not yet convincing), but he has a number of questions about the authors’ interpretation that the creature was a four-winged flyer or glider.

Since few scientists have been able to study the fossils except to look at the pictures, it is not clear if the creature had anything to do with the lineage of birds, or was an oddball that was an evolutionary dead end.

For one thing, Padian is not convinced that the feathers were attached to the rear legs at all, or even if they were, that they were involved in flying or gliding.

“A corollary to this point,“ he says, “is that there is no reason to assume that a gliding animal will necessarily evolve powered flight,” because no bird today, not even Archaeopteryx in the past, used hind limbs in a flight stroke (birds tuck up their feet like airplanes do with their wheels).

“So the leg feathering in Microraptor has nothing demonstrably to do with the evolution of the kind of flight that more derived birds use,” he notes.

Other problems include the claim the hind legs were splayed out to the side, which would have dislocated the hip joint, and that the tibias were bowed, ”which would be extraordinary for any bird or theropod.” Such an arrangement would be useless, he thinks, and hints at distortion of the fossil, because bowed tibiae “would move it farther from anything to do with the origin of birds.”

Padian has some pointed comments about the discoverers’ claim that Microraptor supports the view that flight evolved from the trees down:

Finally, the issue of whether birds evolved flight in trees or on the ground is effectively dead, because it isn't testable. We're not likely to find a fossilized bird in its fossilized tree, about to jump off a fossilized limb. The central problem of the evolution of flight is how the flight stroke evolved, because without it, flapping is not effective. (Also needed are an effective airfoil, a sophisticated neuromuscular apparatus, and an active metabolism for sustained flight.) (italics in original).

Padian supports the alternative view that flight evolved from the ground up, and used their forelimbs originally to trap prey.

It’s kind of fun to watch storytellers argue with each other’s plots. Padian thinks it is incredible that feathered hind limbs would provide any flight benefit to an animal if it were jumping out of trees to learn how to fly, but is it any more credible to claim, without any fossil evidence, that forelimbs used to trap prey would evolve into eagle’s wings?

There is much more involved than just limb shape, as he reminds us. There are muscles, nerves, brain software, hollow bones, a different respiratory system, and much more. In fact, just about every biological system would need redesign for a reptile to evolve powered flight.

This would require hundreds of Darwin’s “successive, slight modifications,” each of which would have had to provide a functional advantage enough to make the lucky mutant survive and all the others die. Great story, if you have enough faith.

Did you catch Padian’s admission that there is no fossil evidence whatsoever for the origin of the flight stroke in powered flight? Did you notice Padian’s reservations about whether the hind legs had feathers at all, and his suggestion that the fossil might have been distorted?

Best of all is his rejoinder about the arboreal origin-of-flight story being untestable, because one cannot see a fossilized bird jumping out of a fossilized tree. But the same criticism can be leveled against Padian’s own preferred story, because one cannot see a fossilized theropod using fossilized forelimbs to catch fossilized prey.

The storytelling is reminiscent of old mountain man Moses Harris, who used to amuse easterners with his tales from the far west. Although petrified forests do exist and had been seen, Moses embellished the account to the point where he described having seen “petrified birds perched on petrified branches of petrified trees, singing petrified songs.”

Given the highly-emotional agenda of some fossil hunters to find missing links, and the known problem of composites coming out of China, it is certainly premature to believe any claims about this fossil. A wait-and-see attitude has proved wise in previous cases.

Source:Creation Evolution Headlines

[bathory]

because we all know Creationism isn't guilty of jumping on the slightest peice of scientific evidence no matter how inconclusive if it can be distorted to prove creationism:)

but yes, i agree with overall message, wait and see

if its wrong, oh well, there's plenty of other evidence

if its right, science +1, creationism +0

interestingly enough, that article is over a year old, perhaps there is something up to date, and perhaps mre conclusive

[Naveed]

Precisly what I was thinking, I heard about this like right after the find. Maybe I can scrounge something up on some paleontology websites. Anyways I hate how that second article looks at this find. Just because the flight may not have been powered, but gliding, or because the feathers may not have had any real use besides looking cool doesn't mean that it discredits evolution. I mean shouldn't the feathers enough be evidence of evolution in the first place? What are the odds non-bird related animals would have feathers anyways? Feathers are a uniquely avian trait, and a lot of those avian features appear in therapod dinosaurs, especially in the dromaeosaur family.

Anyways I don't want to turn this into a debate. Just giving my two cents on the subject.

[KayEl]

You have a point that feathers seem to be a uniquely avian trait that is shared only by extinct dinosaurs. But there is another connection between reptiles and birds: scales! Only a couple of species of mammals have scales (some form of anteater, fogot the name). Birds have scales on their feet just like reptiles. Also, evolutionary speaking, feathers evolved from scales.

Anyway, I do believe birds evolved from dinosaurs: the skeletal structures of all modern birds and certain species of raptors are just too close to be coincidence or an example of parallel evolution.

But also, I think birds have been sufficently changed enough to NOT be considered as dinosaurs.

[SilverCougar]

This also leads into another debate.

Were Dino's warm-blooded?

I mean, birds are warmblooded, yes. And we're finding more and more proof like findings that birds have possibly evolved from dinosaurs. The question is, is the warm-bloodedness of birds also an evolutionary step like feathers, or could it possibly be that dino's or atleast the therapod branch were infact warmblooded themselves?

[doink]

I had heard just the other day about a fossilized four chambered dino heart that was discovered, possibly proving that there were warm-blooded dinos. Anyways, Padian's comments don't all seem to be true, like the part about if the legs splayed out to the side they'd dislocate from the hips, That's how bats fly. There's some cool raptors with feathers that don't seem built for flying but could jump pretty far or whatever reason they had feathers, like Unenlagia, Caudipteryx, and protarchaeopteryx. It is believed that they did not have true powered flight but I'd imagine being able to glide over a rocky slippery slope to catch prey or escape bigger predators must have been an advantage. And, of course, not all birds can fly, ostriches and penguins being the obvious.

[Scorpius]

I had heard just the other day about a fossilized four chambered dino heart that was discovered, possibly proving that there were warm-blooded dinos. Anyways, Padian's comments don't all seem to be true, like the part about if the legs splayed out to the side they'd dislocate from the hips, That's how bats fly. There's some cool raptors with feathers that don't seem built for flying but could jump pretty far or whatever reason they had feathers, like Unenlagia, Caudipteryx, and protarchaeopteryx. It is believed that they did not have true powered flight but I'd imagine being able to glide over a rocky slippery slope to catch prey or escape bigger predators must have been an advantage. And, of course, not all birds can fly, ostriches and penguins being the obvious.

Yes, that explanation seems more plausible and logical. The sketch of this "bird", Microraptor gui, would be more likely to glide than rather fly. Evolving from a ground state, to a gliding state, then to flying state. This makes sense, right?

[Naveed]

Hmm...I'm begining to think we should start a subject on this in Skeptics corner.

Anyways, the other interesting thing that I'd really like to know is what point in time did dinosaurs evolve feathers? Because it seems since Archeaopteryx (sp?) appeared in the jurassic and since their are full fledged birds, even some with teeth in the cretaceaous(sp?), that the dino/feather/bird thing appeared fairly early in the jurassic or perhaps in the very late triassic. Which unfortunatly makes it harder to find specimens from that period since fossils appear to be easier to find the closer they are to our time. And this is a topic that I've thought about for a long time. Maybe I should buy some more books and do some more reading on the subject. Also scrounging the internet works good, but the books are still better since most are written by top paleontologists.

If anyone wants to look up some info for themselves, check out:

http://www.dinosauricon.com/

http://www.dinosauria.com/

[KayEl]

Just because dinosaurs were reptiles doesn't mean they have to be cold blooded. Recent studies in the fossilized bone marrows (!) of dinosaurs showed they have more in common with mammals than with modern day reptiles (something to do with regulating body temperature...it was a long explanation).

I read somewhere that birds have the genes for teeth, but for the most part, it has been "turned off".

And Doink, flightless birds descended FROM flying ancestors, hence they retained their wings. Perhaps in the future these flightless birds might regress back to having hands.

[SilverCougar]

Just because dinosaurs were reptiles doesn't mean they have to be cold blooded. Recent studies in the fossilized bone marrows (!) of dinosaurs showed they have more in common with mammals than with modern day reptiles (something to do with regulating body temperature...it was a long explanation).

I read somewhere that birds have the genes for teeth, but for the most part, it has been "turned off".

And Doink, flightless birds descended FROM flying ancestors, hence they retained their wings. Perhaps in the future these flightless birds might regress back to having hands.

That's the thing...

Reptiles, by some definition are, cold blooded.

If Dinos are proving more and more that they are warm blooded, then that stands reason enough to believe thay arn't repriles.

I mean aside the ones we *know* are, like the giant crocodiles and huge sharks...

But, the only true way to find out, is to clone one. and we all know what happens when you do that...

[Talon]

If Dinos are proving more and more that they are warm blooded, then that stands reason enough to believe thay arn't repriles.

I mean aside the ones we *know* are, like the giant crocodiles and huge sharks...

Could define what you meant by this, it just reads like your claiming sharks are reptiles and Crocodiles are dinosaurs. I take it its just me miss reading?

[doink]

And Doink, flightless birds descended FROM flying ancestors, hence they retained their wings. Perhaps in the future these flightless birds might regress back to having hands.

I'm not arguing that point, I'm merely showing how much variety exists in evolution. Also the question put forth how a ground dwelling dinosaur could evolve to fly, then to how or why a flying bird would evolve to not fly.

[PsychicPenguin]

This is just my theory

I think the dinosour once developed feather to attract opposite sex. It makes individual with longer feather tends to find their partner. In the same time the need for speed made dinos with lighter, streamlined body survived. When the feather is long enough and the body is light enough, the dino would be able to glide, and later they learned how to fly.

Flight might be useful to avoid predator and scouting for preys, but the main food source remains on the ground. Later some birds developed a near-ground lifesytle, similar to pheasants and (wild) chicken. This will allow them to collect more food, but in the same time their ability to fly fast in short distance helped them to avoid predators. With more food, they can become larger.

With larger body size come less predator, until finaly the need of flight is no longer needed, or has become too costly to mantain.

what do you guys think?

[KayEl]

Flightless birds evolved usually out of two reasons: they grew too large for flight, like the ostrich. Instead, they can outrun their predators...or the birds became predators themselves (like the moa).

Or, like the dodo, they have enter an environment without any predators.

[Naveed]

Also look at some of the extinct, predatory brids such as Diatryma(sp?) who also evolved along the lines of the moa, to hunt prey on the ground.

[SilverCougar]

If Dinos are proving more and more that they are warm blooded, then that stands reason enough to believe thay arn't repriles.

I mean aside the ones we *know* are, like the giant crocodiles and huge sharks...

Could define what you meant by this, it just reads like your claiming sharks are reptiles and Crocodiles are dinosaurs. I take it its just me miss reading?

No.. Sharks and crocs were around when the Dino's where, but we know them to be cold blooded.

Sorry, scattered mind at times...